A NEW METHOD FOR THE CALCULATION OF PROPAGATION CONSTANTS AND FIELD PROFILES OF GUIDED MODES OF NONLINEAR CHANNEL WAVE-GUIDES BASED ON THE EFFECTIVE-INDEX METHOD

In this paper, an extension of the effective index method (EIM) to wav eguiding structures containing ideal or saturable third-order nonlinea r materials is presented. By applying separation of variables to the d ominant field component, the complete problem is subdivided into two s calar problems in the lateral and transverse direction, as in the case of the normal EIM. Making use of the strong transverse confinement, a s observed in most real waveguide structures, the nonlinear index chan ges of the various transverse sections can be lumped into nonlinear ef fective indexes of the equivalent layered planar structures. By using these nonlinear effective indexes in self-consistent field calculation s in the transverse direction, a complete approximate solution is obta ined. In this way, the amount of computational effort required for the calculation of the effective indexes and field profiles of the wavegu ides can be reduced significantly.